Contents 16 Hrs Introduction Geometric rep.of the sig waveforms Pulse amplitude modulation 2-d signal waveforms M-d signal waveforms ■Opt.reception for the sig.in AWGN ■Optimal receivers and probs of err UESTC-Digital transmission through the AWGN channel Prof李晓峰 3
5.5 Opt.reception for the sig.in AWGN A general block diagram of a Digital Comm Sys is shown as, s,(t) 5n(t) 十 Mod. Channel Recv Digital communication system The symbols are independent and are represented by specified waveforms.The received signals is often a little different from the sent and we recover the symbols from them. Take antipodal BPAM for msg 1110100... UESTC-Digital transmission through the AWGN channel Prof李晓峰 4
5.5 Opt.reception for the sig.in AWGN In the nth interval ↓ Antipodal BPAM 5m(t) 1 1 1 AWGN channel {,an,} {,an} s() r() am (t)= Recv a n(t)PsD:N。/2 s (t)+n(t) Take antipodal BPAM for msg 1110100... UESTC-Digital transmission through the AWGN channel Prof李晓峰 5
5.5 Opt.reception for the sig.in AWGN In the nth interval,the process is as follows, {,an,} {,an…} s (t) r(t)= Recv s,(t)+n(t) Demod. Detect a It is convenient to divide the receiver into 2 parts: 1)Demodulator:produce an observation from the waveform 2)Detector:estimate the sym from the observation UESTC-Digital transmission through the AWGN channel Prof李晓峰 6
5.5 Opt.reception for the sig.in AWGN In the nth interval,the process is as follows, {,an,} {,an} The topics are: s(t) r(t 1)The Correlation-Demodulators Sm( 2)The MF-Demodulators 3)The Theory of Optimum Detectors 5.6 Typical Optimal Receivers 。 Binary signals r(t) Carrier-amp(1-D signals) Carrier-phs (2-D signals) It is convenient to divide the receiv 。 QAM (2-D signals) 1)Demodulator:produce an obse FSK (M-D orthogonal signals) 2)Detector:estimate the sym from the observation UESTC-Digital transmission through the AWGN channel Prof李晓峰 77